The invention relates to a method for determining the residual range of a motor vehicle which has an energy store for a drive which acts on at least one wheel of the motor vehicle and has an electric motor, as a function of residual energy in the energy store, and a motor vehicle.
Methods for automatically determining a residual range within a motor vehicle have already been known for a relatively long time. In this context, there is very frequently interaction with a navigation system which supplies route data about routes which will be traveled on in future by the motor vehicle. As a function of consumption observations it is then possible to predict how high the consumption will be on the various future route sections, with the result that if the residual energy is known it is possible to determine how far the motor vehicle can still travel on such a route. This can be displayed to a driver, in particular when the driver wishes to assess whether he can still end his journey without refueling or recharging energy in some other way, and in extended cases also whether the residual energy is even still sufficient for a return journey on the same route. In addition, range calculation methods are known which also check various possible future routes.
A method for determining a residual distance which can be covered and an associated arrangement are disclosed by DE 199 29 426 A1. In this context, it is assumed that there is an internal combustion engine, with the result that the residual energy corresponds to a fuel supply. The residual distance which can be covered with the fuel supply is determined from the quantity of the fuel supply and a determined fuel consumption, wherein situation-dependent consumption mean values are used. The core idea in said document is to determine road-class-dependent consumption mean values. Checking is then performed as to which class of road a route section is associated with, with the result that if the length thereof is known, consumption for the route section can be predicted as a function of the consumption mean values. Further classifications are also proposed in said document, for example for the state of charge of the vehicle, the positive gradient and/or a negative gradient of a route section and the like.
New drive concepts have recently been proposed for series production. The drive of the motor vehicle here has an electric motor which can be fed, for example, from a high voltage battery of the motor vehicle. Motor vehicles which have only at least one electric motor and which are frequently also referred to as electric vehicles are known. However, motor vehicles which comprise both an electric motor and an internal combustion engine to drive the vehicle (referred to as hybrid vehicles) have also been proposed. While in motor vehicles which have only one internal combustion engine the internal combustion engine also “pulls along” all the electric consumers (secondary consumers) which are provided in addition to the drive via the dynamo, this is no longer the case with an electric motor which is operated from a store for electrical energy, in particular a high-voltage battery, since the secondary consumers also contribute to the overall consumption from the electric energy store. Known concepts for calculating a residual range do not sufficiently take into account these secondary consumers in order also to make sufficiently reliable statements about the residual range even in the case of operation of an electric motor.